Chemistry involves the study of many different types of reactions and reagents (chemicals in a reaction). Acids and bases (also called alkali) are two of these types of chemicals. Reactions between acids and bases are called a neutralisation reaction. To help teach the principles of these types of reactions to your students or children, have students perform experiments with these chemicals. As with any chemical experiment, ensure that your students are using proper safety equipment, such as goggles, gloves and lab aprons.
Make Your Own Litmus Paper
Litmus paper is used to determine whether a substance is an acid or a base. Students can create litmus paper using red cabbage and white paper, according to instructions on the Fun Science website. To perform this project, the student dices a red cabbage and places the slices in a pot of water. The cabbage is then boiled for a half an hour and the juice removed. This juice has litmus properties. When the white paper is dipped in the juice and then dried, the paper can be used as litmus paper. Red cabbage litmus paper turns red in the presence of an acid and blue in the presence of an alkali.
Testing for Acid or Alkali
Students interested in learning how to determine the alkalinity or acidity of a liquid should learn how to use litmus testing. According to Practical Chemistry, litmus (an indicator) changes colour to show the relative pH of a substance. For this project, the student dips litmus paper into household chemicals, such as soda, toothpaste and shampoo. The student then records her findings, noting which chemicals are alkaline and which are acidic. The household product is more acidic if it turns the litmus paper red. A blue litmus colour change indicates that the tested item is more alkaline, or has more base in it.
A neutralisation reaction occurs when an acid and base react with each other. Neutralisation reactions result in water and a salt, according to the Fun Science website. To perform a simple neutralisation reaction, the student creates a strong solution of basic baking soda and adds acidic vinegar. The resulting reaction creates water, carbon dioxide and the salt, sodium acetate.